I second the comment mentioning the egg crate foam, although really what I think you should do is use a product like dynamat made for car audio, it's just a dense tar like material with an adhesive backing, if you lined the entire inside with that, took out the air filter and just lined the whole thing with the egg crate foam it'd possibly help a db or two. Another experiment I'm curious about is... would just stuffing like pillow stuffing (polyester fiber fill) work well. A stuff animal you don't need or want, an old pillow, anything could be sacrificed to get the "stuffing" out, just take the filter out and put it in. My guess is that the fibers would soak up a lot of the soundwaves. Maybe even steel wool, maybe it being denser than the polyester would help, or some combination of the two. A lot of mufflers have multiple chambers, possibly funneling the sound through a few cardboard sections with a hole in varying spots so the air doesn't have a direct route to the exit hole, but I feel like the polyester fill would work just as well in this application. And for the hoses, maybe hose clamps to ensure theres no air escaping the hose, and then maybe a thicker hose on the outside just to shield it could help a smidge. There's a law of diminishing returns Im sure, but I think a couple of these ideas could be done pretty quick and might help (or would at least be interesting to know if it did anything).

Check out the Ads for the California Air Tool compressors - I am not sure how they do it, but they get the noise down from10 to 20 decibels lower than your compressor, pending on the compressor tested. What ever they are doing seems to be both effective and astonishing.

Michael, I feel a lot of the sound in HF emminates from the mechanical elements of the compressor. We have compressors installed in indoor enclosures at our dental surgery. The enclosures are lined with egg carton shaped foam and the mechanical HF "clatter" is well attenuated. Try directing your meter more specifically at the compressor and look for the telltale HF you are reading on the app to null my hypothesis!!, cheers, Richard

Salut c est pas mal un gros pouce bleu bon week-end 👍👍👍👍👍

Have you ever tried exhaust baffles as well or even a back box off a car?

I have a couple of tractor mufflers that I am going to run outside and hook the intake to them. Just to get the noise outside of my shop. My compressor sets next to the outside wall. Going to do it this weekend and I will post the results. I will have to weld up a adaptor from three cylinders to one with a 2 inch for the muffler. I have all the exhaust pipe to do it It's just a matter of time involved.

mecafer... McCafe... what?

great video!!!

lol

Hmm not too easy to make it better :-(